1. Field of the Invention
This invention relates to the manufacture of flexible image-conducting fiber conduit and has particular reference to improvements in leached optical fiber bundles and method of making same.
2. Description of the Prior Art
Known methods of making leached flexible image-transporting conduit use second claddings of acid-soluble glass on optical fibers or radially-extending fins of acid-soluble glass. U.S. Pat. Nos. 3,624,816 and 3,653,739 are exemplary.
In the case of providing second fiber claddings of leachable glass, the many additional interfaces of the several components needed to make up second claddings and the resulting additional surface areas which become exposed to contamination reduce optical quality of the product, i.e. foreign matter contamination of the various components promotes interfacial gassing and bubble blemishing of critical light-conducting surfaces of the fibers during drawing operations. Also, glasses used in the three-glass fiber fabrication are restricted to combinations having drawing compatibility, i.e. they must have similar temperatures and expansion properties.
In the case of fusing fins of acid-leachable glass to first fiber claddings as in U.S. Pat. No. 3,653,739, considerable tediousness of fiber fabrication, expense and ungainliness of structure is experienced. Accordingly, any advantage of reduced fiber core blemishing can become considerably outweighed by the difficulty and cost of fabrication.
In view of the above, an object of the present invention is to simplify and reduce the cost of manufacturing leached flexible fiber optic conduit.
More particularly, the invention has the objective of overcoming limitations of heretofore lengthy and expensive manufacturing procedures and aims to improve product quality.
Another object is to accomplish the foregoing with greater than usual freedom in the selection of system glasses.
Other objects and advantages of the invention will become more readily apparent from the following description.